Disordered dimer state in electron-dopedSr3Ir2O7

Abstract

Spin excitations are explored in the electron-doped spin-orbit Mott insulator (Sr1−xLax)3Ir2O7. As this bilayer square lattice system is doped into the metallic regime, long-range antiferromagnetism vanishes, yet a spectrum of gapped spin excitation remains. Excitation lifetimes are strongly damped with increasing carrier concentration, and the energy integrated spectral weight becomes nearly momentum independent as static spin order is suppressed. Local magnetic moments, absent in the parent system, grow in metallic samples and approach values consistent with one J = 1 2 impurity per electron doped. Our combined data suggest that the magnetic spectra of metallic (Sr1−xLax)3Ir2O7 are best described by excitations out of a disordered dimer state.

A prototype industrial laser system for cold atom inertial sensing in space

“…Sensitivity, which scales like T 2 in most cold atom inertial sensors, can therefore be greatly improved in microgravity environments [10,11,12]. This makes atomic sensors interesting alternatives to classical instruments for future space missions dedicated to fundamental physics or geodesy [13,14,15,16,17,18].…”

Doping-driven structural distortion in the bilayer iridate (Sr1−xLax)3Ir2O

“…11 The metallic state realized beyond this transition is unconventional with signatures of strong correlation effects, 16 dimer formation, 17,18 negative electronic compressibility, 14 and other electronic anomalies. 19,20 One of the anomalous properties inherent to (Sr 1−x La x ) 3 Ir 2 O 7 is the appearance of a structural distortion below a characteristic temperature T S .…”

Putative magnetic quantum criticality in (Sr1−xLax)3Ir2O7Vale1, Hunter2 2018Phys. Rev. B1000View full textAdd to dashboardCite

“…20,21 Upon electron doping, the spin excitations become progressively more damped. 18,22 Whilst there are discrepancies between the two studies, 23 Lu et al find that the spin gap collapses dramatically for x = 0.065, proposing that the 2D behaviour also extends to the dynamics.We examine some of the previously published experimental data for (Sr 1−x La x ) 3 Ir 2 O 7 in more detail. What we find are three distinct electronic regimes for x > 0.05, which can be discriminated through clear gradient changes in the resistivity as a function of temperature.…”

“…20,21 Upon electron doping, the spin excitations become progressively more damped. 18,22 Whilst there are discrepancies between the two studies, 23 Lu et al find that the spin gap collapses dramatically for x = 0.065, proposing that the 2D behaviour also extends to the dynamics.…”

“…The magnetic (0.5, 0.5, 28) Bragg peak appears to weaken and broaden with increasing temperature, however significant in-plane correlations are still observable at 300 K. Hogan et al also found with RIXS that the magnon peak was invariant with L for their x = 0.07 sample (within experimental uncertainty). 22 Noting that two-dimensional layered materials frequently exhibit such behavior, we proceeded to examine the data in more detail [ Fig. 2(a)].…”